Pump



Aug. 2, 1966 B. LEB'KUCHNER 3,264,653

PUMP

Filed Sept. 18, 1964 5 Sheets-$heet 1 INVENTOR B/m 0 LB/VVCW/Vf/f ORNEYS 2, 1966 B. LEBKUCHNER 3,264,653

4 PUMP Filed Sept. 18, 1964 3 Sheets-Sheet 2 Qz z.

ZZQMJ Y ORNEYS g- 2, 1966 a. LEBKUCHNER 3,264,653

PUMP

Filed Sept. 18, 1964 5 Sheets-$heet s INVENTOR 502220 Leb/mc/mer RNEY5 United States Patent PUMP Benno liebkuchner, Warwick, R.I., assignor to Taco, Inca, (Jranston, KL, a corporation of New York Filed. Sept. 18, 19M, Ser. No. 407,699 21 Claims. (Cl. 103-87) The present invention relates to pumps, and more particularly to a pump having an electric motor connected directly thereto in a manner to enable the fluid being pumped to be introduced into the motor for cooling and lubricating purposes. This application is a continuationin-part of my copending application Serial No. 348,392, filed March 2, 1964, now abandoned.

Pumps having electric motors connected directly thereto so that the fluid being pumped can be introduced directly into the motors are commonly referred to as wet motor pumps. In a wet motor pump the motor housing can be sealed directly to the pump casing to provide an absolutely leak-tight construction which'eliminates the need for the so-oalled stuffing box normally used to prevent the pressurized fluid leaking out around the pump shaft. These pumps are widely used in many different applications, including applications wherein the fluid being pumped is corrosive or contaminated by radioactive particles, or the like. They also are widely used in hot water heating systems where they are commonly referred to as circulators rather than pumps.

One of the disadvantages of wet motor pumps is that the fluid being pumped often contains abrasive foreign particles and impurities which circulate through and are deposited in the bearing clearances of the motor in a manner to accelerate bearing wear. Another disadvantage is that the particles collect on the rotor until they finally block or impede rotation of the rotor. Many attempts have been made to overcome these problems including attempts to filter the particles from the fluid as it passes into the motor. However, it has been found that filters do not provide a satisfactory answer. The aforementioned problems are particularly acute in circulators used in hot water heating systems because a large number of iron oxide particles accumulate in the water. These particles not only cause hearing wear, but also tenaciously collect on the rotor of the motor because they are magnetiz-able.

In accordance with one embodiment of the present invention these problems are overcome by isolating the fluid being pumped in the motor once it has filled the motor. In this way, substantially the same water is retained in the motor while the pump is operating and additional foreign particles in the fluid being pumped are effectively prevented from being introduced into the motor. In a preferred form of the invention as applied to a circulator for a hot water heating system, a seal is actually provided about the common shaft on which the rotor and the impeller are mounted to prevent the water from passing between the pump and motor. In order to fill the motor with water initially, a passageway is formed in the shaft to communicate the impeller chamber, preferably the low pressure side thereof, with the interior of the motor. Thus once the motor is filled additional water cannot get into the motor and the operation of the pump will not draw the water out of the motor. However, as the volume of the water within the motor increases and decreases as a result of temperature changes, the water can move in and out of the shaft at the impeller end to automatically compensate for the changes in volume. This movement of the water will be confined to the passageway in the shaft and primarily be confined to the impeller end thereof where any new foreign particles added cannot affect the hearings or rotor of the motor.

Accordingly, it is one object of the present invention to improve the life and dependability of a wet motor pump.

It is another object of the invention to provide a wet motor pump in which the fluid being pumped is introduced into the interior of the motor but is prevented from circulating through the motor in order to minimize the amount of foreign particles introduced into the motor which cause wear and collect on the rotor to interfere with its rotation.

It is a further object of the invention to provide a wet motor pump having the rotor of the electric motor and the impeller mounted on a common shaft with the fluid being pumped introduced from the pump into the motor solely through passageway means which communicates with the impeller chamber at a position having a specific pressure level so that there is no pressure differential acting across the passageway means to circulate fluid into and out of the motor.

It is a still further object of the invention to provide a wet motor pump of the type described above having a seal slidably engaging the common shaft between the motor and the pump to prevent the fluid being pumped from circulating directly between the pump and the motor, and wherein the common shaft is a hollow shaft which enables the fluid to pass from the impeller chamher into the motor at a point near the rear bearing thereof.

It is a still further object of the invention to provide a wet motor pump of the type described above having a venting arrangement for venting any air trapped in the pump end of the motor after the motor has been filled with the fluid being pumped.

Other objects and features of novelty of the present invention will be specifically pointed out or will otherwise become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is an end view of the pump side of a wet motor pump embodying features of the invention;

FIG. 2 is a sectional view taken along the line 22 of FIG. 1; and

FIG. 3 is an enlarged fragmentary view of a portion of FIG. 2 illustrating a modification of the invention.

Referring to the drawing, a circulator 10 is shown which illustrates features of the invention. The circulator 10 is the type used in hot water heating systems and briefly comprises a pump 12 having an electric motor 15 connected directly thereto so that the fluid being pumped can be introduced into the motor, as will be described, to lubricate the bearings and help cool the motor. Since the circulator 10 is designed for use in a hot water heating system, the fluid being pumped will be water, but of course the invention is applicable to any type of wet motor pump in which the fluid being pumped is introduced into the motor for cooling and lubricating purposes.

The pump 12 comprises a casing 14 having an impeller chamber 16 with an inlet 18 communicating with the eye of the impeller chamber which is the low pressure side of the pump and an outlet 20 communicating with the periphery of the impeller chamber which is the high pressure side of the pump. An impeller 22 is rotatably mounted within the impeller chamber 16 as will be described in greater detail hereinafter.

The electric motor 15 comprises a one-piece housing 24 having an end plate 26 removably mounted thereon to close off the large end of the housing. The motor is mounted directly on the pump casing 14 with a suitable sealing ring 28 interposed therebetween to prevent the water leaking out between the pump casing and end plate Ca 26, the pump casing being provided with an opening 30 in the rear wall thereof to enable the impeller 22 to be positioned within the impeller chamber and consequently enabling the water to communicate directly with the portion of the front face of the end plate within the sealing ring 28.

The end plate 26 has an inwardly extending boss 32 for supporting a front sleeve bearing 34, and the rear wall 46 of the housing 24 is provided with an inwardly extending boss 36 for supporting a rear sleeve bearing 38. Each of the sleeve bearings may be made out of a suitable bearing material such as, for example, one of the well-known sintered bearing materials which enable lubricant to pass through the wall thereof to the bearing surface. Each of the sleeve bearings 34 and 38 is provided with a plurality of circumferentially spaced, axially extending grooves 46 in the outer surface thereof for a purpose which will be described in greater detail hereinafter.

A hollow shaft 52 is rotatably journaled in the bearings 34 and 38 and the rotor 54 of the electric mot-or is fixed to the hollow shaft between the bearings. A sleeve 56 made of a suitable corrosive resistant material such as stainless steel extends over the rotor 54 with the ends thereof sealed to the end plate 26 and rear wall 46 by sealing rings 48 and 50, respectively. Thus, water introduced into the motor through the hollow shaft 52, as will be described, will be confined to the space within the sleeve 56. A two-pole stator 60 is mounted within the housing 24 with the poles thereof positioned on opposite sides of the sleeve 56. The electrical controls for the motor are contained in a small housing 62 mounted on top of the housing 24.

A vent opening 66 is provided in the rear wall 46 of the motor housing 24 and is closed off by a bushing 68 having a vent plug 70 threadably mounted therein. The bushing may be simply press fit in the opening 66 and be made of a suitable corrosive resistant material such as stainless steel. Only the head of the plug 70 is threaded and the reduced end portion thereof seats against a tapered annular seat 72 formed on the inner surface of the bushing 68. The end of the vent plug engaging the seat 72 may be rounded if desired so that it engages the seat in a line contact.

Passageways 74 and 76 are provided in the rear wall 46 of the motor housing to communicate the space between the vent plug 70 and the rear bearing 38 with the space within the sleeve 56. Thus, water from the eye of the impeller chamber can pass through the hollow shaft and passageways 74 and 76 and completely fill the sleeve 56. A seal 78 is mounted within the boss 32 between the front bearing 34 and impeller 22 and slidably seals against the shaft to prevent water passing between the motor and pump. It is apparent that with this construction, the water can get in and out of the motor only through the hollow shaft 52. Thus, 'once the motor is filled, the water will be isolated within the motor when the pump is running and also when the pump is not running. Any change in volume of the water within the motor due to temperature changes will be compensated for automatically because the water is free to move in and out of the impeller end of the hollow shaft 52. If desired, an orifice 80 may be provided in the impeller end of the hollow shaft to restrict the flow of water in and out of the shaft. This restriction, of course, has no effect on the slow movement of water into and out of the hollow shaft due to temperature changes.

A thrust Washer 82 is keyed to the forward end of the rotor 54 by a dish-shaped element 84 which is keyed to the thrust washer and has fingers 86 projecting into recesses in the forward end of the rotor. Radially extending passageways 88 and 90 are provided near the end of the boss 32 to communicate the space between the front bearing 34 and thrust washer 82 with the space within the sleeve 56, and passageways 92 and 94 are provided for communicating the space between the seal 78 and bearing 34 with the space within the sleeve 56. With this construction water within the sleeve 56 will fill the space at both ends of the bearing 34 and the grooves 40 in the outer periphery of the bearing.

It has been observed that slight pressure differences in the proximity of both bearings exist due to the rotation of the shaft 52 and rotor 54. These pressure differences cause the water within the sleeve 56 to circulate through both bearing clearances. In order to reduce the effect of this circulation and thus further reduce the deposition of foreign matter within the bearing clearances, the axial grooves 40 are provided near the bearing clearances to channel all but the amount of fluid needed for lubrication through the grooves 40. Of course axial passageways extending through the bearings near the bearing clearances may be used in place of the grooves 40, and grooves can be provided in the bearing surfaces. Further the ratio of the areas of the grooves in the inner and outer surfaces of each bearing can be made to determine the amount of water flowing through the LD. of the bearings.

The impeller 22 is keyed to the end of the hollow shaft 52 projecting into the impeller chamber and a thrust washer 96 is positioned between the impeller and end plate 26. In the preferred form of the invention illustrated, a plurality of axial grooves 98 are formed in the bore of the impeller 22 to communicate the rear face of the impeller with the eye of the pump. This reduces the fluid pressure on the side of the seal 78 adjacent to the impeller and minimizes the pressure differential across the seal. With this arrangement, a relatively inexpensive seal can be employed and still effectively prevent the flow of water therethrough.

By isolating the water within the motor in accordance with the present invention, the impurities or foreign particles, such as iron oxide particles found in the water of hot water heating systems, which are introduced into the motors are held to an absolute minimum. In prior wet motor pumps, these particles are slowly but continuously introduced into the motor because the fluid being pumped is circulated under pressure into the motor at one point and out at another point. In many prior wet motor pumps, the fluid is continuously forced under pressure out through the front motor bearing clearance which sig nificantly reduces the life of the bearing. Filters have been employed to filter the fluid passing into the motor, but it has been found that they do not provide the answer to the problem. In comparison to these prior wet motor pumps, wet motor pumps embodying the present invention will have far superior reliability and life due to the significant increase in the life of the motor bearings and the elimination of excessive accumulation of iron oxide particles on the rotor surf-ace.

Referring to FIG. 3, an arrangement is shown for venting air from the pump end of the wet motor pump illustrated in FIGS. 1 and 2. A plurality of small crossdrilled passageways 100 are provided in the hollow shaft 52 at a point between the seal and front bearing 34. The diameters of the passageways preferably are made as small as possible so that foreign particles in the water cannot pass into the chamber defined by the sleeve 56. If desired, a porous bushing 102, such as a sintered metal bushing, can be mounted within the hollow shaft 52 in position to cover the ends of the passageways 100 to filter out foreign particles. In filling the sleeve 56, the water will follow the path of least resistance, which is through the hollow shaft, past the rear bearing into the sleeve and around the rotor into the pump end of the sleeve. With this venting arrangement, any air trapped in the pump end of the sleeve 56 after the sleeve has been filled with Water will be vented through the cross-drilled passageways 100, and the wall of the bushing 102, if the bushing is used.

The above described venting arrangement is particularly important for applications wherein the wet motor pump is mounted in a vertical position with the pump above the motor. If air is trapped in the pump end of the motor in such an application, the unit can operate with considerable noise for a period of time and some bearing wear may occur. The venting arrangement described promptly vents the air after the pump is started to avoid this problem in a very effective manner.

It also will be observed in FIG. 3 that a lip-type seal 104 made of a suitable material, such as rubber, is used in place of the felt seal illustrated in FIG. 2. This type of seal slidably engages the shaft in substantially a line contact to minimize the possibility of dirt accumulating between the seal and shaft as might eventually occur in the embodiment of FIG. 2. The lip of the seal extends toward the impeller which is the high pressure side of the seal so that any pressure differential will tend to increase the pressure with which the seal slidably engages the shaft.

While it will be apparent that the embodiment of the invention described is well calculated to fulfill the objects of the invention, it will be appreciated that the invention is susceptible to variation, modification and change without departing from the proper scope or fair meaning of the subjoined claims. For example, a solid shaft could be substituted for the hollow shaft 52 and a restricted passageway could be formed in the end plate 26 at a position between the boss 32 and the sealing ring 48 for communicating the impeller chamber with the space within the sleeve 56. With this arrangement the water within the motor would have the disadvantage of being pressurized but it still would be isolated within the motor rather than circulating therethrough.

Although the preferred embodiment of the invention described employs a sleeve 56 to prevent the water from contacting the stator, it is apparent that the sleeve could be eliminated so that the water could flow around the stator if the stator were protected with a suitable water repellant material. Also the impeller end of the hollow shaft 52 can be closed off and cross drilled holes provided to communicate the hollow shaft with the space between the impeller 22 and seal 78. This arrangement would effectively reduce the pressure differential across the seal to zero.

What is claimed is:

1. A wet motor pump comprising a pump casing having an impeller chamber and an inlet and outlet communicating with the impeller chamber, an electric motor having a housing with a rotor therein and a shaft rotatably driven by said rotor with said shaft projecting from one end of the housing, bearing means within said housing for rotatably journaling said rotor, means for sealingly connecting the motor housing and pump casing together with said shaft extending into said impeller chamber, an impeller positioned within the impeller chamber and drivingly connected to said shaft, and seal means [for providing a seal around said shaft adjacent to said one end of the motor housing to completely seal said housing against fluid circulating into the interior of the motor housing, said shaft having passageway means therein communicating a chamber within the motor housing with the impeller chamber, said lbearing means communicating with said motor chamber which can be filled with the fluid being pumped for lubricating and cooling said bearing means and wherein the fluid within said motor chamber can communicate with the fluid in the impeller chamber in a manner to compensate for changes in volume of the fluid within said motor chamber.

2. The invention as defined in claim 1 wherein said passageway means communicates with the low pressure side of said impeller chamber.

3. The invention as defined in claim 1 wherein said passageway means has a restriction therein to retard the movement of fluid in said passageway means.

4. The invention as defined in claim 1 wherein said shaft is a hollow shaft.

5. The invention as defined in claim 4 wherein said motor comprises a stator fixed within said housing, a

rotor fixed on said shaft and a bearing mounted in said housing near each end of said rotor for journaling the shaft in said housing, said seal means being located between the impeller and the bearing adjacent thereto, each of said bearings communicating with said chamber.

6. A wet motor pump comprising an electric motor having the rotor thereof mounted on a shaft which projects from one end of the motor, bearing means for journaling said shaft, a pump having an impeller chamber with an inlet and outlet communicating with the peller chamber, means for sealingly connecting said pump and motor together with said shaft extending into said impeller chamlber, an impeller positioned within said impeller chamber and drivi-ngly connected to said shaft for rotation therewith, means for sealing a chamber within said motor against fluid circulating into and out of said motor chamber, and passageway means providing the sole communication between the pump and said motor chamber whereby the fluid being pumped can flow between the motor and pump chambers only through said passageway means, said bearing means communieating with said motor chamber so as to be lubricated by fluid in said mot-or chamber, said passageway means communicating with the pump at a position wherein the fluid is at a specific pressure whereby the fluid in the motor chamber can not be subjected to a pressure differential which would circulate fluid into and out of the motor chamber and whereby the fluid within said motor chamber can communicate with the fluid in said impeller chamber in a manner to compensate for changes in volume of the fluid within said motor chamber.

7. The invention as defined in claim 6 including seal means for providing a seal about said shaft at a position between the impeller and bearing means adjacent thereto.

8. A wet motor pump comprising an electric motor having the rotor thereof mounted on a shaft which projects from one end of the motor, bearing means notatably journaling said shaft within said housing, a pump, means for sealing-1y connecting said pump and motor together with said shaft extending into the interior of said pump and drivingly connected to the impeller thereof, and seal means positioned between the motor and pump for sealing said housing against fluid circulating into and out of a chamber within said motor, said shaft having a passageway means formed therein, one end of said passageway communicating with the interior of said pump and the other end of said passageway communicating with a chamber within said motor whereby the fluid being pumped can enter said motor chamber only through said passageway means and the fluid within said motor chamber can communicate with the fluid in said pump in a manner to compensate for changes in volume of the fluid within said motor chamber, said bearing means communicating with said motor chamber so as to be lubricated by fluid within the motor chamber.

9. The invention as defined in claim 8 wherein said passageway means extends from one end of the shaft to the other.

It. A wet motor pump comprising an electric motor having a hollow rotor shaft journaled therein by bearings positioned at each end of the rotor, said hollow shaft projecting from one end of the motor, a pump, means for sealingly mounting said pump on said one end of the motor with said hollow shaft projecting into the pump, an impeller fixed on the end of the shaft projecting into the pump, and seal means positioned between the pump and motor and slidably sealing about said shaft to seal said motor against fluid circulating into the motor whereby the fluid being pumped can enter and leave the motor only through said hollow shaft and the fluid within the motor can communicate with the fluid being pumped to compensate for changes in volume of the fluid within said motor, the interior of said motor being arranged and 7 constructed to be filled with fluid and when filled both of said bearings being exposed to the fluid within the motor to be lubricated thereby.

11. A wet motor pump comprising a motor housing having axially aligned openings in the ends thereof, a sleeve bearing mounted in each of said openings, a hollow shaft journaled by said sleeve bearings and projecting from one end of said motor housing, a rotor fixed on said shaft between said bearings, a stator mounted Within said housing about said rotor, an impeller mounted on the projecting end of said shaft, a pump casing positioned over said impeller, means sealingly mounting said pump casing on said motor housing, seal means positioned between said impeller and the motor bearing adjacent thereto for sealing the motor housing against fluid circulating into the interior of the motor housing other than through said hollow shaft, a vent plug closing off the opening in the motor housing adjacent to the other end of said shaft, and passageway means in said motor housing for communicating said other end of the hollow shaft with the interior of the motor housing and both of said bearings whereby the fluid within the interior of said motor housing can communicate with the fluid in the pump casing in a manner to compensate for changes in volume of the fluid within the interior of the motor hous- 12. The invention as defined in claim 11 including passageway means for communicating one side of the impeller with the other whereby the pressure differential between opposite sides of the impeller is minimized.

13. The invention as defined in claim 11 wherein each of said bearings have axially extending passageways associated therewith for enabling fluid to flow freely from one end of the bearing to the other without passing through the clearance between the bearing and the shaft, and wherein said motor housing has passageway means therein for communicating the spaces adjacent to the ends of the front bearing with the interior of the motor to enable fluid to flow freely around the front bearing.

14. The invention as defined in claim 11 including :a sleeve extending between the rotor and stat-or substantially concentric with the axis of said shaft, and seal means for sealing each end of said sleeve to said motor housing, said passageway means in said motor housing communieating the space adjacent to the other end of said hollow shaft with the space within said sleeve.

15. A wet motor pump comprising an electric motor having the rotor thereof mounted on a shaft which projects from one end of the motor, a pump, bearing means adjacent to each end of said rotor for rotatably journaling the rotor within said motor, means for sealingly mounting said pump on said one end of the motor with said shaft projecting into the pump, an impeller drivingly connected to the end of the shaft projecting into the pump, passageway means in said shaft for introducing the fluid being pumped into said motor at a point rearwardly of the rearward end of said rotor furthest removed from said pump to lubricate the bearing means adjacent to said rearward end of the rotor, a seal positioned between said impeller and rotor and slidably sealing about said shaft to prevent the fluid from passing between the pump and motor, the interior of said motor being constructed and arranged to deliver fluid entering at the rearward end of said rotor past the rotor to the forward end thereof to lubricate the bearing means adjacent to the forward end of the rotor, and vent means for communicating the interior of said motor between the forward end of said rotor and said seal with said passageway means in said shaft.

16. The invention as defined in claim 15 wherein said vent means comprises a small cross-drilled passageway in said shaft .between said seal and rotor and a porous bushing mounted in said shaft in position to cover the ,inner end of said cross-drilled passageway.

having a hollow rotor shaft journaled therein by bearings at both ends of the rotor, said hollow shaft projecting from one end of the motor, a pump, means for sealingly mounting said pump on said one end of the motor with said hollow shaft projecting into the pump, an impeller drivingly connected to the end of the shaft projecting into the pump, seal means positioned between said impeller and the bearing adjacent thereto, said hollow shaft introducing the fluid being pumped into said motor at a point rearwardly of the rear motor bearing to fill the motor with the fluid, and vent means in said shaft communicating the space between said seal and adjacent bearing with the interior of said hollow shaft whereby air trapped in the forward end of the motor can be vented through said vent means.

18. A wet motor pump comprising an electric motor having the rotor thereof mounted on a shaft which projects from one end of the motor, bearing means Within said motor for rotatably j-oui'naling said shaft within 'the motor, a pump, means for sealingly connecting said pump and motor together with said shaft extending into the interior of said pump and drivingly connected to the impeller thereof, and seal means positioned between the motor and pump for sealing said motor against fluid circulating into and out of the interior thereof, said shaft having passageway means formed therein, one end of said passageway means communicating with the interior of said pump and the other end of said pasasgeway communicating with the interior of said motor whereby the fluid being pumped can enter said motor only through said passageway means and the fluid within said motor can communicate with the fluid within the pump in a manner to compensate for changes in volume of the fluid within the motor, the interior of said motor being constructed and arranged to deliver fluid from said passageway menas to said bearing means to lubricate the bearing means, said seal means having an annular lip pnojecting inwardly toward said impeller and slidably engaging said shaft in substantially a circular line contact.

19. A wet motor pump comprising a pump having an inlet and an outlet, 21 motor sealingly connected to said pump, said motor having a movable driven element journaled therein by bearing means, shaft means extending from the interior of said motor into the interior of said pump, the mot-or end of said shaft means being connected to said driven element and the pump end of said shaft means actuating said pump to pump fluid from said inlet out through said outlet, seal means positioned between said pump and motor for sealing said motor against fluid circulating into and out of the interior thereof, and passageway means in said shaft means for communicating the interior of said pump with the interior of said motor to enable fluid to pass therebetween, the interior of said motor being arranged and constructed to deliver the fluid from said passageway means to said bearing means to lubricate the bearing means whereby the fluid within said motor can commtmicate with the fluid in said pump in a manner to compensate for changes in volume of the fluid within said motor.

20. A wet motor adapted to be drivingly connected to a pump for pumping fluid comprising an electric motor having a sealed chamber therein for receiving the fluid being pumped, a rotor positioned within said chamber, bearing means for rotatably journaling said rotor within said chamber, :a shaft one end thereof projecting from said motor and the other end thereof drivingly connected to said rotor, passageway means in said shaft having one end thereof communicating with said one end of said shaft and the other end thereof communicating with said chamber to enable fluid to enter said chamber to lubricate said bearing means, and seal means on said motor sealingly engaging the surface of said shaft for sealing said fluid within said chamber so that it can enter and leave said chamber only through said passageway means.

21. A wet motor adapted to be drivingly connected to a pump for pumping fluid comprising an electric motor having a sealed chamber therein, a stator and a rotor mounted on a hollow shaft, at least said hollow shaft mounted rotor being positioned within said chamber, bearing means within said chamber rotatably journ'aling said hollow shaft to rotatably support said rotor within said chamber, one end of said hollow shaft projecting from said motor and the other end thereof communicating with said chamber to enable fluid to enter said chamber to lubricate said bearing means, and seal means on said motor sealingly engaging the surface of said shaft for sealing the fluid within said chamber so that it can enter and leave said chamber only through said hollow shaft.

References Cited by the Examiner UNITED STATES PATENTS McConaghy 10387 Kaatz 103-87 White et a1. 10387 Smith 10387 Granqvist 103-87 McMahan 10387X H aegh 10387 ROBERT M. WALKER, Primary Examiner. 

1. A WET MOTOR PUMP COMPRISING A PUMP CASING HAVING AN IMPELLER CHAMBER AND AN INLET AND OUTLET COMMUNICATING WITH THE IMPELLER CHAMBER, AN ELECTRIC MOTOR HAVING A HOUSING WITH A ROTOR THEREIN AND A SHAFT ROTATABLY DRIVEN BY SAID ROTOR WITH SAID SHAFT PROJECTING FROM ONE END OF THE HOUSING, BEARING MEANS WITHIN SAID HOUSING FOR ROTATABLY JOURNALING SAID ROTOR, MEANS FOR SEALINGLY CONNECTING THE MOTOR HOUSING AND PUMP CASING TOGETHER WITH SAID SHAFT EXTENDING INTO SAID IMPELLER CHAMBER, AN IMPELLER POSITIONED WITHIN THE IMPELLER CHAMBER AND DRIVINGLY CONNECTED TO SAID SHAFT, AND SEAL MEANS FOR PROVIDING A SEAL AROUND SAID SHAFT ADJACENT TO SAID ONE END OF THE MOTOR HOUSING TO COMPLETELY SEAL SAID HOUSING AGAINST FLUID CIRCULATING INTO THE INTERIOR OF THE MOTOR HOUSING, SAID SHAFT HAVING PASSAGEWAY MEANS THEREIN COMMUNICATING A CHAMBER WITHIN THE MOTOR HOUSING WITH THE IMPELLER CHAMBER, SAID BEARING MEANS COMMUNICATING WITH SAID MOTOR CHAMBER WHICH CAN BE FILLED WITH THE FLUID BEING PUMPED FOR LUBRICATING AND COOLING SAID BEARING MEANS AND WHEREIN THE FLUID WITHIN SAID MOTOR CHAMBER CAN COMMUNICATE WITH THE FLUID IN THE IMPELLER CHAMBER IN A MANNER TO COMPENSATE FOR CHANGES IN VOLUME OF THE FLUID WITHIN SAID MOTOR CHAMBER. 